Hydraulic brake mechanism

ABSTRACT

A hydraulic brake mechanism is mountable to a bicycle handlebar. The hydraulic brake mechanism includes a housing having a base portion and an extension portion, the base portion including first and second ends, the base portion including a handlebar clamp at the first end, the base portion extending generally horizontally and the extension portion extending forwardly of the base portion at the second end and angled generally upwardly from the base portion when the hydraulic brake mechanism is mounted to the bicycle handlebar, the housing sized and shaped to be grasped by a user&#39;s hand, the housing having a fluid outlet port in the extension portion. The hydraulic brake mechanism may include a fluid line attached to the fluid outlet port and disposed in a groove formed along a length of the extension portion and the base portion of the housing.

This application is a continuation application under 37 C.F.R. §1.53(b)of U.S. patent application Ser. No. 14/851,666, filed Sep. 11,2015,which is a continuation of U.S. patent application Ser. No. 14/226,271,filed Mar. 26, 2014, now U.S. Pat. No. 9,156,522. which is acontinuation of U.S. patent application Ser. No. 13/351,000, filed Jan.16, 2012, now U.S. Pat. No. 8,714,322, all of which are herebyincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

The invention relates to a hydraulic brake system. More particularly,the invention relates to a hydraulic brake actuation mechanism used witha hydraulic brake for engaging a wheel of a vehicle, such as forexample, a bicycle.

Many vehicles, such as for example bicycles, utilize a hydraulic brakesystem that applies pressure to a rotating wheel, or a disc mounted to arotating wheel. Some of these braking systems utilize a mechanismincluding a hand lever, to generate pressure in a hydraulic fluid. Thispressure is transferred through a hydraulic line or conduit to a brakeassembly, which may include a caliper having pads, such that thehydraulic pressure is applied to the pads to squeeze the pads againstthe rotating part to impart a braking force.

SUMMARY OF THE INVENTION

In light of the present need for an improved hydraulic brake actuationmechanism, and in particular a mechanism that is provided in an overallergonomic package, a brief summary of various exemplary embodiments ispresented. Some simplifications and omissions may be made in thefollowing summary, which is intended to highlight and introduce someaspects of the various exemplary embodiments, but not to limit the scopeof the invention. Detailed descriptions of a preferred exemplaryembodiment adequate to allow those of ordinary skill in the art to makeand use the inventive concepts will follow in later sections.

In one aspect of some embodiments of the invention a hydraulic brakemechanism is mountable to a bicycle handlebar. The hydraulic brakemechanism includes a housing having a base portion and an extensionportion, the base portion including first and second ends, the baseportion including a handlebar clamp at the first end, the base portionextending generally horizontally and the extension portion extendingforwardly of the base portion at the second end and angled generallyupwardly from the base portion when the hydraulic brake mechanism ismounted to the bicycle handlebar, the housing sized and shaped to begrasped by a user's hand, the housing having a fluid outlet port in theextension portion. The hydraulic brake mechanism may also include ashift device disposed in the housing, a fluid chamber disposed in theextension portion of the housing in fluid communication with a fluidreservoir and the fluid outlet port, and a piston movably disposedwithin the fluid chamber. The hydraulic brake mechanism may also includea lever pivotally disposed at the second end of the base portion, thelever operatively connected to the piston to slidably displace thepiston within the fluid chamber. The hydraulic brake mechanism may alsoinclude a fluid line attached to the fluid outlet port and disposed in agroove formed along a length of the extension portion and the baseportion of the housing.

In another aspect of some embodiments of the invention a housing for ahydraulic brake mechanism sized and shaped to be grasped by a user'shand and mountable to a bicycle handlebar. The housing includes a baseportion including first and second ends, the base portion including ahandlebar clamp at the first end, the base portion extending generallyhorizontally, and an extension portion extending forwardly of the baseportion at the second end and angled generally upwardly from the baseportion when the housing is mounted to the bicycle handlebar. Thehousing also may include a fluid outlet port in the extension portion, afluid reservoir, and a fluid outlet port. The housing may also include ashift device space configured for the inclusion of a shift device, and alever attachment portion disposed at the second end of the base portion,the lever attachment portion configured to be operatively connected tothe piston to slidably displace the piston within the fluid chamber. Thehousing may also include a fluid chamber configured to include a pistonmovably disposed therein, the fluid chamber disposed in the extensionportion of the housing and in fluid communication with the fluidreservoir and the fluid outlet port, and a groove formed along a lengthof the extension portion configured to house a fluid line attached tothe fluid outlet port.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand various exemplary embodiments, referenceis made to the accompanying drawings, wherein:

FIG. 1 is a side view of a brake hood including a brake actuationmechanism and a shift actuation mechanism according to an embodiment ofthe invention;

FIG. 2 is a front view of the mechanism of FIG. 1, showing a brake leverand hood;

FIG. 3 is a cross-sectional view through lines 3-3 of the mechanism ofFIG. 2;

FIG. 4 is a front view of the mechanism of FIG. 1, showing a brake leverand hood;

FIG. 5 is a cross-sectional view through lines 5-5 of the mechanism ofFIG. 2;

FIG. 6 is a top view of a second embodiment of a brake actuationmechanism according to the invention, with part of the housing removedto reveal the arrangement of elements at or near the top of the brakeactuation mechanism;

FIG. 7 is a top view of the brake actuation mechanism of FIG. 6, showinginternal structure;

FIG. 8 is an exploded isometric view of the brake hood and mechanism ofFIG. 1;

FIG. 9 is a partial isometric view of the internal chambers andpassageways of the brake actuation mechanism of FIG. 6;

FIG. 10 is a side view of the brake actuation mechanism of FIG. 6,showing internal structure;

FIG. 11 is a side view of the brake actuation mechanism of FIG. 10,showing internal structure;

FIG. 12 is a perspective view of the brake actuation mechanism, showingthe top and a side of the brake hood;

FIGS. 13-15 are side sectional views showing the brake actuationmechanism in use showing an initial travel, at-rest condition (FIG. 13),a fully actuated or full travel condition (FIG. 15), and an intermediatecondition between the at rest and the full travel condition (FIG. 14);and

FIGS. 16a-16e are diagrams of a fluid chamber and outlet port accordingto several different embodiments.

DETAILED DESCRIPTION

Various embodiments of the invention provide for a hydraulic brakeactuation mechanism, which may in some cases include another componentsuch as, for example, a shift actuation mechanism. The mechanismdescribed herein is well suited for use in handlebar-steered vehiclessuch as, for example, bicycles. It will be understood that thepositional/directional references will be used herein according to theirordinary meaning unless specifically set out hereinbelow, with thehydraulic brake actuation mechanism of the invention mounted to avehicle, and wherein the vehicle is oriented according to normal use.One embodiment will now be described futher below, with reference to thedrawing figures.

Referring to FIGS. 1-15, a hydraulic brake actuation mechanism 20 for ahandlebar-steered vehicle, according to the invention, includes ahousing 22. The housing 22 may be made of any suitable material, forexample: aluminum, plastic, composites, and/or carbon fiber. A mastercylinder assembly 26 is disposed at least partially within the housing22. An actuator, which may be in the form of a brake lever 30 ispivotally attached to the housing 22 and is operably connected to themaster cylinder assembly 26. A shift mechanism 56 may be positioned inor on the housing 22. The shift actuation mechanism 56 may be attachedto or disposed within the housing 22, as is known in the art, and isactuated by a shift lever 58 or other shift mechanisms such as one ormore switches, such that both braking and shifting operations can beperformed while the user grasps the housing 22, and thus maintainscontact and control of the vehicle while braking and/or shifting. In oneexample, the shift actuation mechanism may be a control mechanism suchas that described in U.S. Pat. No. 7,779,718.

Generally, the housing 22 may be considered to include a housing body27. The housing body 27 is a single-piece molded construction or formedof more than one piece. The housing body 27 may be considered to includea base portion 23 and an extension portion 25. The housing 22 ismountable to a part of the handlebar-steered vehicle, for example by aclamp 24 attached to the base portion 23 of the housing body 27. Thehousing 22 may be arranged on a handlebar of the vehicle pointing in theforward direction, i.e., pointing in the forward travel direction (F) ofthe vehicle during normal use, oriented generally along the longitudinalaxis of the vehicle, with the base portion 23 generally alignedhorizontally and the extension portion 25 generally forward of the baseportion and angled generally upwardly from the base portion whenmounted.

The housing 22 also may include a first cover part 29 that closes thehousing body 27 on at least one flank or lateral side thereof and asecond cover part 31 that closes the housing body on a top or upper sidethereof. The first cover 29 permits access to the interior of thehousing body 27 for installation, removal, and maintenance of elementsof the hydraulic brake actuation mechanism 20 that are reachable throughthe side of the housing body. The first cover 29 may also cover part ofthe top surface 70 of the housing body 27 (FIG. 6) and cooperate withthe second cover 31, and housing body to present a smooth, comfortableshape for a user's hand while covering elements of the interiormechanism.

The second cover part 31 permits access to the interior of the housingbody 27 for installation, removal, and maintenance of elements of thehydraulic brake actuation mechanism 20 that are reachable at or throughthe top of the housing body. The covers 29, 31 also may complete anergonomic shape with the housing body 27, and when assembled to form thehousing 22 may receive a hood cover 62, which may be an elastomericmaterial.

The hydraulic brake actuation mechanism 20 includes a master cylinderassembly 26 which may be disposed within the housing body 27 and may bedisposed in the extension portion 25. The master cylinder assembly 26may be generally oriented along the longitudinal axis of the extensionportion 25, as will be seen in more detail hereinbelow. It will beunderstood that the master cylinder assembly 26 is connectable to aconventional slave cylinder (not shown) by a hydraulic line or conduit28 which provides fluid communication therebetween.

As shown in FIG. 6, the master cylinder assembly 26 includes a fluidchamber 32 that is formed within the housing body 27 and a pistonassembly 34 that is reciprocally disposed within the fluid pressurechamber. The fluid chamber 32 includes first and second chamber portions42, 44 and a transition region 46 located therebetween.

In the embodiment shown in FIG. 9, the first chamber portion 42 has agreater cross-sectional area or diameter (d₁) than a cross-sectionalarea or diameter (d₂) of the second chamber portion 44. In thisembodiment, the transition region 46 is tapered but may have a differentshape or may be eliminated entirely, for example, by a steppedtransition between first and second chamber portions 42, 44. The firstand second chamber portions 42, 44 in this embodiment are cylindrical;however, the portions may take a variety of shapes. It will beunderstood that the shape of the first and second chamber portions 42,44 will be matched in shape by the relevant parts of the piston assembly34 and any seals functioning therebetween.

One end 48 of the second chamber portion 44, i.e. a distal end, isdirectly or indirectly in fluid communication with a bleed or fill port50 formed in the housing 22. A bleed port screw 52 is removably disposedin the bleed port 50 to permit bleeding of air or the addition of fluid.The bleed port screw 52 is provided with a seal 53, which is for examplean O-ring. The end 48 is also directly or indirectly in fluidcommunication with a fluid reservoir 40 formed in the housing body 27,for example, by way of a passageway 82 that may interconnect the bleedport 50 and the fluid reservoir.

The reservoir 40 is capped by a bladder 84, in a known fashion (FIG. 8).In order to provide an ergonomic overall shape to the housing 22, andprovide sufficient brake fluid volume for the hydraulic brake actuationmechanism 20, the reservoir 40 may be positioned along the side of thefluid chamber 32, and may extend vertically both above and below thefluid pressure chamber, with the housing mounted to a drop handlebar,for example. In other words, when the hydraulic brake actuationmechanism 20 is mounted for use on a vehicle, the reservoir 40 may bepositioned in a side-by-side configuration with the fluid chamber 32,and has a shape and size that extends both vertically above and belowthe fluid pressure chamber.

A fluid outlet port 60 is formed in the housing body 27 connecting thefluid chamber 32, in the vicinity of the transition region 46, to afluid fitting assembly 54. The fluid fitting assembly 54 includes ahollow bolt 64 which is in fluid communication with the fluid outletport 60, for example—threadably inserted into the fluid output port. Thefluid fitting assembly 54 includes a “banjo” fitting 66, connected toand in fluid communication with the hollow bolt 64. The banjo fitting 66is similar to conventional banjo fittings, except the bottom surface 68of the banjo fitting is not oriented normal to the axis of the hollowbolt. In the illustrated embodiment, the angle (A) of the hollow bolt 64(and the fluid outlet port 60) is greater than 90 degrees, angledrelative to the top or upper surface 70 of the housing 22 (FIG. 11).Therefore, in order for the banjo fitting 66 to lie flush on the surface70 of the housing, the invention contemplates a banjo fitting that hasbeen modified by orienting the bottom surface 68 of the fitting to matchthe top surface or upper surface 70 of the housing body 27.

Due at least in part to the construction of the fluid fitting assembly54, the housing body 27 can closely accommodate the fitting 54, andhydraulic line 28 attached thereto, in such a way that the hydraulicline can lie parallel to the surface 70, and thus presents a low profilethat permits the housing 22 to be designed ergonomically. Because of thelow profile configuration, the hood cover 62 can be smoothly fitted overthe housing 22, including the fluid fitting assembly 54 and hydraulicline 28, and thus the fit of hood cover and the overall shape is notinterrupted or negatively affected by any projecting hydraulic lines orelements.

The housing body 27 additionally may have a groove 72 that generallyruns along the length of the housing that accommodates the hydraulicline 28 such that a smooth contour is presented that conforms to thehand of the user. In the illustrated embodiment, the groove 72 is formedat or near the junction of the top surface and side surface of thehousing body 27. Other positions of the groove 72 may be possible, suchas along the side of the housing body 27. With respect to ergonomics,the first cover part 29 may be configured to wrap over the hydraulicline 28 and at least partially enclose the groove 72.

The piston assembly 34 includes a piston 74 reciprocally disposed withinthe fluid chamber 32. The piston 74 has first and second portions 76,78. A first seal 36, in this embodiment, a combination of a glide ringand an O-ring, is disposed on the first portion 76 of the piston 74 anda second seal 38 is disposed on the second portion 78 of the piston 74.Other types of suitable seals are contemplated. In an alternativeembodiment, the seals 36, 38 may be positioned in the walls of the fluidchamber 32, and contact the piston 74.

The first and second portions 76, 78 carrying respective first andsecond seals 36, 38 are configured to sealingly engage respective firstand second chamber portions 42, 44 of the fluid chamber 32. When soengaged, first and second seals 36, 38 define an output chamber 80therebetween (FIG. 5). The fluid outlet port 60 may extend from theoutput chamber 80 in the vicinity of the transition region 46 (FIG. 9).

The piston 74 is slidably displaceable between an open fluid circuitposition that permits fluid flow between the first and second chamberportions 42, 44 of the fluid chamber 32 and a closed fluid circuitposition (FIG. 5) that blocks fluid flow between the first and secondchamber portions 42, 44. When the piston 74 creates the closed circuitposition, i.e., when both first and second seals 36, 38 are engaged withrespective first and second chamber portions 42, 44 of the fluid chamber32, the act of advancing the piston (into the fluid pressure chamber)causes fluid pressure to build in the output chamber 80 because of thereduction in volume caused by the advancing piston. The increase offluid pressure in the output chamber 80 causes fluid to be forced fromthe chamber and through the fluid outlet port 60. Due to theconfiguration of the fluid chamber 32 it can be seen that the fluidoutlet port 60 may be positioned in fluid communication with the outputchamber 80 in the vicinity of the transition region 46. Accordingly, thefluid outlet port 60 may extend from the fluid chamber 32 at or near thetransition region 46 or the first chamber portion 42 of the fluidpressure chamber, although an amount of fluid connection with some ofthe second chamber portion 44, particularly at or near the transitionregion may also be effective as long as the port 60 can receivepressurized fluid generated between seals 36, 38. Advantageously, duringa cycle of operation, the piston 74 may advance in the fluid chamber 32of the master cylinder assembly 26 in a generally upward direction withthe output chamber 80 located in a relatively low point in the mastercylinder assembly.

When the piston 74 creates the closed circuit position, i.e., when bothfirst and second seals 36, 38 are engaged with respective first andsecond chamber portions 42, 44 of the fluid chamber 32, fluid in thesecond chamber portion 44 is advanced into the reservoir 40. Themovement of fluid into (and out of) the reservoir 40 tends to displacethe bladder 84. Air above the bladder 84 may be vented to atmospherethrough the second cover 31 to permit movement of the bladder as aresult of the change of volume of fluid in the reservoir 40.

The piston assembly 34 also includes a return spring 86, which may bedisposed in the fluid chamber 32 between the housing body 27 and thepiston 74 and functions to return the piston 74 and lever 30 to a startposition generally corresponding to the open circuit position. A plate88 is attached to the housing body 27 to close the first chamber portion42 of the fluid chamber 32, retain the piston assembly 34 within thefluid pressure chamber, and provide access to the piston 74 via a platehole 90.

A pushrod 92 may be disposed in the plate hole 90 and acts upon thepiston assembly 34 via the lever 30. The pushrod 92 may include athreaded portion 96 proximate one end and a head 94 proximate the otherend. The head 94 may include a rounded surface 112, which is received ina corresponding cup surface 114 in the piston 74. The threaded portion96 of the pushrod 92 is threadably received in cross dowel 98.

The dowel 98 may be pivotally disposed with a bushing 100. The lever 30pivotally receives the bushing 100 and dowel 98. The pushrod 92 passesthrough the dowel 98. The pushrod 92 may include a hex opening 116 forreceiving an Allen wrench for adjusting the position of the lever 30, orreach, relative to a handlebar (not shown) by threaded engagement withthe dowel 98.

The lever 30 is pivotally attached to the housing body 27 by way of apivot assembly 104. The pivot assembly 104 may include a shaft 106. Theends of the shaft 106 may include bushings 108 that enable movementbetween the lever 30 and the housing body 27. Clips 110 may be affixedto the shaft 106 to retain the pivot assembly 104 on the housing body27.

Referring to FIGS. 13-15 in particular, a typical cycle of operationincludes a hand brake application to push brake pads against a brakerotor (not shown) or rim. The brake lever blade 30 is depressed by hand.This pushes the pushrod 92 to advance the piston 74. The lever blade 30starting position may be changed with the adjustment of the pushrod 92in the dowel 98. The piston 74 includes the first seal 36, which is thelarger seal that always seals fluid from the atmosphere, and a secondseal 38 that is not in sealing engagement when the lever blade is notdepressed (FIG. 13), which represents an initial travel, at-restcondition.

Within the reservoir 40, a flexible bladder 84 makes a barrier betweenthe fluid and atmosphere (FIG. 8). As the piston 74 is advanced, thefirst seal 36 continues to seal fluid from atmosphere and the secondseal 38 becomes engaged with the fluid chamber 32 in the vicinity of thetransition region 46 to create the closed circuit condition orintermediate condition (FIG. 14). When the second seal 38 becomesengaged, it creates a seal between the reservoir 40 and forms the outputchamber 80.

The output chamber 80 and port 60 include a volume of fluid. The outputchamber 80 is connected to a fitting 54 that is connected to a remotebrake caliper (not shown). As the lever blade 30 is depressed further(FIG. 15), pressure increases in the output chamber 80, fluid is movedthrough the fitting 54, typically through a hydraulic line 28 (FIG. 8),and into the brake caliper.

As is well known, a pressure increase in the brake caliper causes thecaliper pistons to advance and brake pads are urged against a brakerotor to create braking forces. If used with hydraulic rim brakes, thepressure increase causes the hydraulic rim brakes to engage a bicyclerim. When the lever blade 30 is released, the piston 74 returns to its“at rest” position, at least through action of the return spring 86, thepressure in the system decreases, and the caliper pistons/brake padsretract from the rotor/rim and brake forces decrease. The second seal 38finally becomes disengaged from the wall of the fluid chamber 32creating the open circuit condition.

FIGS. 16a-16e are diagrams of fluid pressure chambers 32 with outletports 60 shown in positions corresponding to several differentembodiments of the invention. Each of FIGS. 16a-16e include fluidchambers 32 with first chamber portion 42 and second chamber portion 44with a transition region 46 positioned therebetween as noted in theexamples shown in FIGS. 1-15. The second chamber portion 44 has a distalend 48 and an end opposite the distal end, which will be referred to asthe proximate end 120, adjacent the transition region.

FIG. 16a shows the outlet port 60 extending from the first chamberportion 42 near the transition region 46. FIG. 16b shows the outlet port60 extending from both the first chamber portion 42 and the transitionregion 46. FIG. 16c shows the outlet port 60 extending from thetransition region 46. FIG. 16c shows the outlet port 60 extending fromthe second chamber portion 42 and the transition region 46. FIG. 16eshows the outlet port 60 extending from the second chamber portion 42 atthe proximate end 120, near the transition region 46.

Although the various exemplary embodiments have been described in detailwith particular reference to certain exemplary aspects thereof, itshould be understood that the invention is capable of other embodimentsand its details are capable of modifications in various obviousrespects. As is readily apparent to those skilled in the art, variationsand modifications can be affected while remaining within the spirit andscope of the invention. Accordingly, the foregoing disclosure,description, and figures are for illustrative purposes only and do notin any way limit the invention, which is defined only by the claims.

What is claimed is:
 1. A hydraulic brake mechanism mountable to abicycle handlebar, the hydraulic brake mechanism comprising: a housinghaving a base portion and an extension portion, the base portionincluding first and second ends, the base portion including a handlebarclamp at the first end, the base portion extending generallyhorizontally and the extension portion extending forwardly of the baseportion at the second end and angled generally upwardly from the baseportion when the hydraulic brake mechanism is mounted to the bicyclehandlebar, the housing sized and shaped to be grasped by a user's hand,the housing having a fluid outlet port in the extension portion; a shiftdevice disposed in the housing; a fluid chamber disposed in theextension portion of the housing in fluid communication with a fluidreservoir and the fluid outlet port; a piston movably disposed withinthe fluid chamber; a lever pivotally disposed at the second end of thebase portion, the lever operatively connected to the piston to slidablydisplace the piston within the fluid chamber; and a fluid line attachedto the fluid outlet port and disposed in a groove formed along a lengthof the extension portion and the base portion of the housing.
 2. Thehydraulic brake mechanism of claim 1, further comprising a fluidreservoir in fluid communication with the fluid chamber.
 3. Thehydraulic brake mechanism of claim 2, further comprising a bleed port influid communication with the fluid chamber.
 4. The hydraulic brakemechanism of claim 3, wherein the housing is formed one piece and thefluid reservoir is formed in the housing.
 5. The hydraulic brakemechanism of claim 4, wherein the fluid reservoir is disposed in theextension portion of the housing.
 6. The hydraulic brake mechanism ofclaim 5, wherein the housing further comprises a fluid passageway formedin the housing, the fluid passageway extending laterally between thefluid chamber and the fluid reservoir.
 7. The hydraulic brake mechanismof claim 1, wherein the housing is further configured to include a spacefor the shift device.
 8. The hydraulic brake mechanism of claim 7,further comprising a hood cover configured to be fitted over the fluidline and shift device.
 9. The hydraulic brake mechanism of claim 8,further comprising a hood cover made of an elastomeric material, thehood cover being configured and arranged to at least partially cover thebase portion.
 10. The hydraulic brake mechanism of claim 1, wherein thefluid line is constrained to the base portion of the housing.
 11. Thehydraulic brake mechanism of claim 10, wherein the fluid line isconstrained by a cover part attached to the housing.
 12. The hydraulicbrake mechanism of claim 10, wherein the fluid line is constrained at aposition on the base portion of the housing closer to the handlebarclamp than the extension portion.
 13. The hydraulic brake mechanism ofclaim 1, wherein the groove is formed at a side surface of the housing.14. The hydraulic brake mechanism of claim 13, wherein the groove isformed at an intersection of the side surface and a top surface of thehousing.
 15. The hydraulic brake mechanism of claim 1, furthercomprising a hood cover configured to be fitted over the fluid line. 16.The hydraulic brake mechanism of claim 1, wherein the fluid reservoir islocated in the extension portion and the lever is pivotally disposedbelow the fluid reservoir while the hydraulic brake mechanism is mountedto the bicycle handlebar.
 17. A housing for a hydraulic brake mechanismsized and shaped to be grasped by a user's hand and mountable to abicycle handlebar, the housing comprising: a base portion includingfirst and second ends, the base portion including a handlebar clamp atthe first end, the base portion extending generally horizontally; anextension portion extending forwardly of the base portion at the secondend and angled generally upwardly from the base portion when the housingis mounted to the bicycle handlebar; a fluid outlet port in theextension portion; a shift device space configured for the inclusion ofa shift device; a fluid reservoir; a fluid chamber configured to includea piston movably disposed therein, the fluid chamber disposed in theextension portion of the housing and in fluid communication with thefluid reservoir and the fluid outlet port; a lever attachment portiondisposed at the second end of the base portion, the lever attachmentportion configured to be operatively connected to the piston to slidablydisplace the piston within the fluid chamber; and a groove formed alonga length of the extension portion configured to house a fluid lineattached to the fluid outlet port.